• Terminal 5 is a common terminal for the frequency setting signal input (via terminal 2 or 4). It should be protected from Signal inputs by contactless switches external noise using a shielded or twisted cable. The contact input terminals of the inverter (STF, STR, RH, RM, RL) can be controlled using a transistor instead of a contact switch as shown below. +24V Inverter PC +24V STF, etc SD Inverter R STF, etc External signal input using transistor (sink logic) External signal input using transistor (source logic) 2.6.4 Wiring precautions • It is recommended to use a cable of 0.3 to 0.75 mm 2 for the connection to the control circuit terminals.
• The wiring length should be 30 m at the maximum. • Use two or more parallel micro-signal contacts or twin contacts to prevent contact faults when using contact inputs since the control circuit input signals are micro-currents. Micro signal contacts Twin contacts • To suppress EMI, use shielded or twisted cables for the control circuit terminals and run them away from the main and power circuits (including the 200 V relay sequence circuit). For the cables connected to the control circuit terminals, connect their shields to the common terminal of the connected control circuit terminal.
When connecting an external power supply to terminal PC, however, connect the shield of the power supply cable to the negative side of the external power • Always apply a voltage to the fault output terminals (A, B, C) via a relay coil, lamp, etc. supply. Do not directly earth (ground) the shield to the enclosure, etc. 40 2. INSTALLATION AND WIRING 2.6 Control circuit